The present invention relates to a cassette loading apparatus for use in magnetic recording/reproducing apparatuses such as a video tape recorder.
Various types of cassette loading apparatuses for use in magentic recording/reproducing apparatuses such as a video tape recorder are known and usually employ a so-called front loading system in which a tape cassette is inserted through a front opening. Although such a front loading type cassette loading apparatus functions satisfactorily, it requires a number of assembling steps due to its relatively complex structure. For this reason, the cassette loading apparatuses have hitherto been assembled separately from bodies of the magnetic recording/reproducing apparatuses.
More specifically, as shown in FIGS. 1 and 2, a prior art cassette loading apparatus includes a cassette holder 1 for releasably holding a type cassette (not shown) such as a video tape cassette and side plates or side frames 2 and 3 provided at opposite right and left sides of the cassette holder 1. L-shaped guide slots 8 and 10 are formed in the right side plate 2, while L-shaped guide slots 9 and 11 are formed in the left side plate 3. Projecting pins 4 and 6 are mounted on the right side of the cassette holder 1 so as to be held in engagement with the right side plate within the guide slots 8 and 10 of the right side plate 2, respectively. Likewise, projecting pins 5 and 7 are mounted on the left side of the cassette holder 1 so as to be held in engagement with the left side plate within the guide slots 9 and 11, respectively. Drive arms 12 and 13 for moving the cassette holder 1 between a first position and a second position (loadig position) are provided at the side plates 2 and 3, respectively. Assuming that the known cassette loading apparatus is disposed horizontally, the cassette holder 1 is moved horizontally and vertically as the projecting pins 4, 5, 6 and 7 move along the guide slots 8, 9, 10 and 11, respectively. Reference numerals 4a and 5a show the projecting pins 4 and 5 disposed at the second or loading position. The drive arm 12 has a toothed portion 12a. Although not specifically shown, the drive arm 13 also has a toothed portion similar to the toothed portion 12a of the drive arm 12. A drive motor 16 transmits a driving force, via a worm 17, a worm wheel 18 and a gear 19, to the toothed portion 12a. The gear 19 is fixed to one end of a shft 20 which is rotatably supported by the side plates 2 and 3. Another gear 21 is fixed to the other end of the shaft 20 in engagement with the toothed portion of the drive arm 13.
A cassette guide 22 is provided for guiding the tape cassette when the tape cassette is inserted into the cassette holder 1 and for coupling the side plates 2 and 3 with each other. A top plate 23 is provided for coupling the side plates 2 and 3 with each other at an upper portion of the known cassette loading apparatus and for imparting rigidity to the entire known cassette loading apparatus.
The prior art cassette loading apparatus shown in FIG. 1 is assembled as follows. Initially, the cassette holder 1 and the side plates 2 and 3 are positioned such that the projecting pins 4 to 7 are received in or engaged with the guide slots 8 to 10 of the side plates 2 and 3, respectively. Generally, to this end, the cassette holder 1 is secured to a jig (not shown) and then, the side plates 2 and 3, which are placed accurately at opposite sides of the cassette holder 1, are slowly shifted towards the cassette holder 1 such that the projecting pins 4 to 7 are received in the guidie slots 8 to 10, respectively. The drive motor 16, the worm 17 and the worm wheel 18 are attached to the right side plate 2 in advance as a drive unit, a description of the assembling steps of the drive unit is omitted.
Subsequently, opposite ends of the cassette guide 22 are secured to the side plates 2 and 3, respectively. Then, the drive arms 12 and 13 are rotatably attached to a shaft 14 extending between and projecting outwardly from the side plates 2 and 3 such that the projecting pins 4 and 5 of the cassette holder 1 are, respectively, received in guide slots 15a and 15b formed in the drive arms 12 and 13, respectively. Thereafter, the left gear 21 is press fitted to one end of the shaft 20 and then, the shaft 20 having the gear 21 mounted thereon is fitted through the side plates 3 and 2. Then, the right gear 19 is attached to the other end of the shaft 20 and is fixed by an E-shaped ring 32. The gears 19 and 21 are positioned by adjustig the engagement of the teeth so that the drive arms 12 and 13 move synchronously with each other. The top plate 23 is attached to the side plates 2 and 3 by screws 24a, 24b, 24c and 24d such that the high strength and highly accurate assembling of the known cassette loading apparatus are ensured. Thus, the assembling of the known cassette loading apparatus is completed.
However, in the known cassette loading apparatus having the above described construction, the side plates 2 and 3 are required to be slowly shifted towards the cassette holder 1 such that the projecting pins 4 to 7 are, respectively, received in the guide slots 8 to 11 of the side plates 2 and 3. To this end, a relatively large and and complex jig for assembly is needed. Furthermore, the known cassette loading apparatus is disadvantageous in that a relatively long time period is required for the assembly thereof.
Moreover, the known cassette loading apparatus has a drawback in that after the shaft 20 having the gear 21 secured thereto has been fitted through the side plates 3 and 2, the gear 19 is required to be mounted on the shaft 20 so as to coincide, i.e. be in phase, with the gear 21, thereby resulting in a time delay in its assembling.